The present invention relates to a specific composition comprised of a mixture of gangliosides which mixture has been found to possess important analgesic or pain relieving activity.
Gangliosides represent a family of complex glycolipid molecules which are natural components of cellular membranes, in particular of neuronal membranes. These components are implicated in neuronal development, differentiation and regeneration processes. Exogenously applied gangliosides will insert into neuronal membranes in a stable manner. This incorporation is associated with the activation of a membrane-bound enzyme system, (Na.sup.+, K.sup.+) ATPase whose activity is essential for nerve impulse conductivity. Ganglioside prepreparations have been shown to possess a reinnervation-stimulating activity due to enhanced nerve sprouting, an essential feature of muscular reinnervation processes and of restoration of synaptic contacts. Electrophysiological and functional evidence of early recovery, due to parenteral ganglioside treatment, from nerve damage has been obtained in several animal models, including sensory nerve function after nerve transection, cochlear impairment by noise, diabetic neuropathy in mutant diabetic mice and intoxication
Gangliosides are acidic glycolipids belonging to the family of biological compounds called glycosphingolipids. They are composed of 4 basic structural units: a long-chain animoalcohol, a fatty acid, an oligosaccharide moiety and one or more sialosyl residues.
1. The long-chain aminoalcohol, present in brain gangliosides is identified as 4-sphingenine and its longer-chain analog as 4-eicosasphingenine; these compounds are commonly called sphingosines. ##STR1##
The corresponding saturated compounds (sphinganines) are also present in gangliosides in minor proportions.
2. A fatty acid is linked by means of an amide bond to the sphingosine base. In brain gangliosides this fatty acid is more than 95% accounted for by stearic acid (18:0). Other fatty acids are encountered in minor proportions, i.e. arachidic acid (20:0), palmitic acid (16:0) or palmitoleic acid (16:1.DELTA..sup.9). The aminoalcohol plus the fatty acid form the unit termed ceramide, which represents the hydrophobic part of the ganglioside molecule.
3. The oligosaccharide chain linked to ceramide characterizes the large family of glycosphingolipids to which gangliosides belong. The spingolipids are classified in two subgroups, based on the carbohydrate immediately linked to ceramide. The first and smaller subgroup derives from galactosyl-ceramide.
Most of the glycosphingolipids, and thus virtually all gangliosides, belong to the subgroup derived from glucosyl-ceramide.
4. Sialic acid is present in brain gangliosides mainly in the N-acetyl form, but in some ganglioside species the N-glycolyl form has been identified. This residue is generally termed neuraminic acid (NANA or NGNA). ##STR2##
The hydrophilicity of gangliosides is due to the oligosaccharide chain and to the number of sialosyl residues linked to this chain.